21531343 has 2 divisors, whose sum is σ = 21531344. Its totient is φ = 21531342.

The previous prime is 21531337. The next prime is 21531361. The reversal of 21531343 is 34313512.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21531343 - 2¹⁷ = 21400271 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21531043) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765671 + 10765672.

It is an arithmetic number, because the mean of its divisors is an integer number (10765672).

Almost surely, 2^21531343 is an apocalyptic number.

21531343 is a deficient number, since it is larger than the sum of its proper divisors (1).

21531343 is an equidigital number, since it uses as much as digits as its factorization.

21531343 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1080, while the sum is 22.

The square root of 21531343 is about 4640.1878194746. The cubic root of 21531343 is about 278.1999450095.

Adding to 21531343 its reverse (34313512), we get a palindrome (55844855).

The spelling of 21531343 in words is "twenty-one million, five hundred thirty-one thousand, three hundred forty-three".